jar-inspector-mcp

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jar_class_outline

Read-only

Retrieve a class's API outline from a JAR—declaration, annotations, fields, and method signatures—without decompiling or reading source.

Instructions

Show a class's API: declaration, annotations, fields and method signatures.

This is the cheap alternative to decompiling or reading source. Signatures keep generics, parameter names (when compiled with -g), thrown exceptions and constant values; method bodies are not included.

Args: jar: Archive path, classes directory, or outer.jar!nested.jar. class_name: FQCN, simple name or glob (resolved like jar_find_class). visibility: Lowest visibility to include: public, protected, package, private. include_synthetic: Include compiler-generated bridge/synthetic members. fully_qualified_types: Print java.util.List instead of List.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "jar": "<jar>",
      "class_name": "<class_name>"
    },
    "name": "jar_class_outline"
  }
}

Input Schema

Name	Required	Default
`jar`	Yes
`class_name`	Yes
`visibility`	No	protected
`include_synthetic`	No
`fully_qualified_types`	No

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 4, 2026

TDQS

A4.8/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only say readOnlyHint=true and openWorldHint=false, so the description carries meaningful extra value. It details what is included (declaration, annotations, fields, method signatures, generics, parameter names under -g, thrown exceptions, constant values) and explicitly what is not included (method bodies), giving an agent an accurate model of behavior.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact, well-structured, and front-loaded. The first sentence states the purpose, the second adds key trade-offs, and the Args block provides necessary parameter detail without redundancy. Every sentence contributes information not already present in the schema.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read-only outline tool, the description is complete: it covers input formats, resolution behavior, output scope, caveats about debug symbols, and exclusions. An output schema exists to define return values, so the description does not need to repeat those details. The only external reference, 'resolved like jar_find_class', is reasonable since that sibling already exists in the toolset.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must explain all parameters, and it does. Each param gets a concrete explanation: jar accepts paths or nested-jar syntax, class_name accepts FQCN/simple/glob and references jar_find_class resolution, visibility gives the allowed values, and the two booleans are explained with examples.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb and resource: 'Show a class's API: declaration, annotations, fields and method signatures.' It clearly differentiates this from related tools by framing it as 'the cheap alternative to decompiling or reading source' and by stating that method bodies are not included, which distinguishes it from jar_read_source and jar_disassemble.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It provides clear context for when to choose this tool: when only an API outline is needed and decompiling/source is overkill. It also notes the exclusion of method bodies, which signals when another tool would be needed, though it does not explicitly name those alternative siblings or provide a when-not-to-use list.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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